colloid, substance consisting of ultramicroscopic particles suspended in another substance. Wine colloids are very finely divided solids in particles with diameters ranging from about five nanometres to one micrometre. These are principally large organic molecules, most of which are polymers made of polysaccharides including pectins, and of smaller molecules such as phenolics, pigmented tannins, and tannins (see polymerization). They do not contribute to a wine’s viscosity. When fining and filtration are successfully accomplished, less than 20% of colloids are removed so that wine quality is not affected.
